/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.state;



import com.bff.gaia.unified.sdk.annotations.Experimental;

import org.joda.time.Instant;



import javax.annotation.Nullable;



/** Interface for interacting with time. */

@Experimental(Experimental.Kind.TIMERS)

public interface Timers {

  /**

   * Sets a timer to fire when the event time watermark, the current processing time, or the

   * synchronized processing time watermark surpasses a given timestamp.

   *

   * <p>See {@link TimeDomain} for details on the time domains available.

   *

   * <p>Timers are not guaranteed to fire immediately, but will be delivered at some time

   * afterwards.

   *

   * <p>An implementation of {@link Timers} implicitly scopes timers that are set - they may be

   * scoped to a key and window, or a key, window, and trigger, etc.

   *

   * @param timestamp the time at which the timer should be delivered

   * @param timeDomain the domain that the {@code timestamp} applies to

   */

  void setTimer(Instant timestamp, TimeDomain timeDomain);



  /** Removes the timer set in this context for the {@code timestmap} and {@code timeDomain}. */

  void deleteTimer(Instant timestamp, TimeDomain timeDomain);



  /** Returns the current processing time. */

  Instant currentProcessingTime();



  /** Returns the current synchronized processing time or {@code null} if unknown. */

  @Nullable

  Instant currentSynchronizedProcessingTime();



  /** Returns the current event time. */

  Instant currentEventTime();

}